A motor pump and control manifold assembly

ABSTRACT

A motor pump assembly is provided that comprises a motor, a drive shaft connected to the motor, a pump and control manifold including means for controlling fluid flow to and/or from the pump. The motor, drive shaft, pump and manifold are contained within a single common housing. The manifold forms an integral part of the housing and includes a pump chamber that contains the pump.

The present invention relates to a motor pump and control manifoldassembly, and in particular a motor pump assembly for use in controllinga hydraulic actuator.

A hydraulic system comprising a hydraulic actuator such as a hydrauliccylinder requires a pump for driving fluid to the actuator, and drivemeans such as a motor for driving the pump. A control manifold is alsorequired to control and direct the pressurised hydraulic fluid from thepump and the depressurised fluid flowing to tank. FIG. 1 shows anexample of a hydraulic drive system. The system comprises an electricmotor 1 contained within a motor housing 2. A pump 4 is contained withina pump housing 6. The pump housing 6 is connected to the motor housing 2and the drive shaft of the motor (not shown) connects to the shaft ofthe pump via a coupling and drives the pump 4. A fluid outlet line 8connects the outlet of the pump 4 to a control manifold 10 containing aseries of control valves. The control manifold in turn includes a fluidoutlet that may be connected to the supply port of a hydraulic actuator.A return line 12 connects the control manifold 10 to the inlet port ofthe pump 4. The control manifold 10 also connects to the outlet port ofthe hydraulic actuator and to tank. A support frame 14 connects themotor 1, pump 4 and control manifold 10. The size and/or cost of such anarrangement may be prohibitive for certain applications.

It is therefore desirable to provide an improved motor pump and controlmanifold assembly which addresses the above described problems and/orwhich offers improvements generally.

According to the present invention there is provided a motor pumpassembly as described in the accompanying claims.

In an embodiment of the invention there is provided a motor pump andcontrol manifold assembly assembly comprising a motor, a drive shaftconnected to the motor, a pump and control manifold including means forcontrolling fluid flow to and/or from the pump.

The motor, drive shaft, pump and manifold are contained within a singlecommon housing. The term ‘single common housing’ is a term whichcontrasts with the prior art in which each of the motor, pump andmanifold are contained in independent, separately formed housings thatare operatively connected, but at least one or more of which isindependent of and physically separated from the others. Locating themotor, drive shaft, pump and manifold within an integrated housingadvantageously obviates the requirement for a network of pipeworkinterconnecting a number of separate components and enables the size ofthe assembly to be minimised. The manifold may comprise an integral partof the housing, and the term ‘contained within’ does not thereforerequire the manifold to be an independent component located within aseparate housing; rather that at least the working elements of themanifold, namely the fluid channels and valves, are at least partiallycontained within the housing.

The housing preferably comprises a main housing body containing each ofthe motor, drive shaft, pump and manifold. The housing may comprise afirst section housing the motor, and a second section comprising thepump housing and manifold, the first and second sections being securedto each other and the shaft extending through both the first and secondsections. The term ‘single piece’, with reference to the entire housing,or the first and second sections, means that the body of the relevanthousing section is formed as a single piece, and does not exclude thehousing or housing sections from including additional components or‘parts’ such as end plate covers, port connections or closure members.

Preferably the manifold is integrally formed as part of the housing, inthat the valve chambers and associated fluid channels and ports areformed within a body which defines the housing. The manifold thereforeforms one of the housing sections, within which the pump is contained.Forming the manifold such that it is comprises part of the housingremoves the requirement for external pipes and connectors to connect aseparate manifold to the pump. As well as reducing part numbers, thisalso simplifies assembly and reduces leak paths.

Preferably the housing includes an integrally formed pump chamberconfigured to house the pump, which may be a vane pump or gear pump orany other suitable pump arrangement. The pump chamber is fluidlyconnected to the manifold within the housing body. The pump chamber ispreferably formed within the manifold.

The housing preferably further includes an integrally formed chamber forhousing the motor. The motor and pump are both connected within thehousing to the single common drive shaft. The term ‘single common driveshaft’ means that the shaft is continuous and unbroken along its length.A single bearing is preferably provided along the drive shaft betweenthe motor and the pump, which is enabled by the use of a single pieceshaft contained within a common housing. In contrast, in arrangements ofthe prior art an independent pump and motor are provided, each havingseparate drive shaft elements that must be connected when theindependent are assembled together.

The pump chamber of the housing preferably includes an inner side wallwhich locates axially inwards of the pump. A closure member is providedat the opposing axial side of the pump, the closure member forming theouter side wall of the pump chamber. The pump preferably comprises agear pump cartridge or a vane pump cartridge consisting of a cam ringand a plurality of vanes mounted to the drive shaft. The pump cartridgeis clamped and secured directly between the inner and outer walls. In anembodiment where a vane pump is used, this arrangement removes therequirement for separate cheek plates or other additional components tosecure and port the pump, thereby enabling the size of the assembly tobe reduced, and in particular a reduction in the axial length.

Preferably the fluid channels of the control manifold are axiallylocated between the pump chamber and the motor chamber. This arrangementenables the pump to be located at the end of the assembly for ease ofassembly. The housing may include one or more integrally formed heatexchange fluid channels having a pathway extending proximate a wall ofthe motor chamber. Preferably a matrix or network of channels are formedto flow through the housing proximate the inner wall of the motorchamber. The manifold may be configured to channel and control fluidflow through the heat exchange fluid channels to assist in cooling themotor. Locating the manifold adjacent the motor chamber advantageouslyfacilities this arrangement and limits the length of the coolingchannels.

The motor pump assembly may comprise at least one control manifoldmodule including one or more valves. The control manifold module isprovided in addition to the control manifold and optionally connectableto the control manifold. The control manifold module is configured tosecure to and fluidly connect with the control manifold. The controlmanifold module comprises a manifold body and one or more control valvesand additional ports configured to provide additional controlfunctionality to the motor pump assembly. For example, the controlmanifold may include a port and valve arranged to control fluid supplyto a primary hydraulic cylinder and an auxiliary cylinder, and thecontrol manifold module may include valves arranged to control fluidsupply to one or more additional auxiliary cylinders.

The control manifold preferably includes one or more fluid portsarranged for connection to the at least one control manifold module.These may be the inlet and outlet ports of the control manifold that inthe basic configuration i.e. without additional manifold modulesconnected, connect directly to the primary and/or auxiliary cylinders.Alternatively additional ports may be included in the control manifoldthat may be accessed by the control manifold module when connected tothe main control module. The main control manifold and the controlmanifold module include corresponding connections means that enable thecontrol manifold module to be bolted or otherwise secured to the controlmanifold.

The control manifold module preferably includes connector elementsarranged to enable a further control manifold module to be securedthereto in a similar manner to which it is secured to the main controlmanifold. As such, the functionality of the motor pump assembly may beselectively increased and modified in a modular manner through theaddition of further control manifold modules. This enables a universalmotor pump unit to be manufactured which is able to be selectivelymodified through the addition of control manifold modules depending onthe required functionality, rather than multiple different units, with afixed configuration and functionality.

Preferably at least the part of the housing comprising the controlmanifold and the pump chamber is a single piece body, for example thepart of the housing comprising the control manifold and the pump chambermay be a single piece casting.

In an aspect of the invention there is provided a motor pump assemblycomprising a motor, a drive shaft connected to the motor, a pump andcontrol manifold including means for controlling fluid flow to and/orfrom the pump. The manifold defines a housing which contains the pump.The motor is contained within the housing and/or is contained with ahousing section that is directly connected to the manifold, the motorhousing and manifold combining to define a housing assembly.

The present invention will now be described by way of example only withreference to the following illustrative figures in which:

FIG. 1 shows a motor pump assembly according to the prior art; and

FIG. 2 shows a motor pump assembly according to an embodiment of thepresent invention.

Referring to FIG. 1 there is a provided a hydraulic drive system 18comprising an electric motor 20, a gear pump 22 and control manifold 24.The motor 20 is preferably a permanent magnet motor. In the arrangementof FIG. 2 two permanent magnets are arranged in series, but it will beappreciated that in other embodiments one of more than two motors may beprovided. A drive shaft 23 is connected to the motor 20 at a first end21 and extends axially from the motor 20. The gear pump 22 is packagedwithin a pump cartridge 25 that is mounted to the shaft 23 at the secondend 26 which functions as the pump rotor. Advantageously only a singlecommon shaft is required within the assembly that directly couples toboth the motor 20 and the pump 22.

A roller bearing 32 is located between the motor 20 and the pumpcartridge 25 that rotationally supports the shaft 23. As the assemblyutilises a common shaft, advantageously only a single bearing isrequired along the length of the shaft 23. In contrast, in arrangementssuch as that of FIG. 1, where a pump unit is bolted to a separate motorunit, two bearings are required along the shaft in the pump unit as wellas in the motor unit. The applicant has further identified that thehydraulic pressure at the tips of the pump vanes supports the shaft 23at the second end such that no additional bearing is required at thesecond end. The lower inherent side-load generated by the gear pump 22as compared to other pump types further allows the shaft support bearingdesign to be optimized.

A housing 34 contains all of the components of the assembly. The housingis preferably a two part housing, although could be manufactured as asingle piece casting. A first section of the housing 34 defines motorchamber 36 located at a first axial end of the housing 34. The motorhousing 36 has an inner end wall 38 which closes the motor chamber 36.The end wall 38 includes an axial bore 40 through which the shaft 23extends. The inner wall 38 may be formed as part of the first motorchamber section 35 of the second housing section 37. The bore 40 extendsaxially towards the second end and includes a first diameter section 42that houses the bearing 32. A second stepped down section 44 of reduceddiameter houses a shaft seal 45 to prevent egress of hydraulic fluid tothe motor 20 along the shaft 23. A third section 46 defines a pumpchamber having a diameter sized to receive the vane cartridge 25.Between the second and third sections the bore 40 has a diametersubstantially equal to the diameter of the shaft 23, sized to permitfree rotation of the shaft 23 within the bore 40.

The pump chamber 46 has an inner wall 48. A closure plate or cap 50closes the open outer end of the pump chamber 46. The inner surface 52of the end plate 50 defines the outer wall of the valve chamber 46. Theclosure plate 50 is bolted in position to the end wall of the housing34, and acts to clamp the pump cartridge in position against the innerwall of the pump chamber 46. The inner wall 48 of the pump chamber 46 ispreferably an integrally formed part of the housing 34, formed in thecasting process. The ports for the pump 22 are formed in the inner wall48. By clamping the vane cartridge between the closure plate 50 and theinner wall 48, and by forming the ports of the pump 22 in the end wall48, the cheek plates that are conventionally provided to clamp and portand pump are no longer required, which reduces the number of parts,simplifies assembly and reduces cost.

The housing 34 further includes a control manifold section 54. Themanifold section 54 is arranged between the pump 22 and the motor 20.The manifold section 54 is integrally formed as part of the single piecehousing 34. The manifold section 54 includes a plurality of ports, suchas port 56, arranged to receive control valves such as cartridge valve58, to control fluid flow to and from the pump 22. The pump extendsdirectly from the inner wall porting face 48 of the pump chamber 46 intothe manifold section 54, with the outer face of the manifold 54 formingthe porting face 48 of the pump 22. Integrating the control manifolddirectly in the assembly housing obviates the requirement for a systemof pipework connecting the pump with a separate control manifoldassembly, thereby enabling the overall size of the assembly to bedrastically reduced. Integrating the manifold into the housing alsosignificantly simplifies assembly and greatly reduces parts. Theintegrated manifold 54 also enables the flow to and from the pump 22 tobe readily controlled such that either port of the pump may bepressurised. This enables the pump 22 to be operated in a firstdirection as a pump and in a second direction as a motor driving theelectric motor 20 to function as a generator. The assembly is thereforeideally suited to applications in which energy recovery from a hydraulicsystem is required.

In a further advantage, fluid channels (not shown) may be formed in themanifold that are routed through the manifold 54 in a region immediatelyadjacent the inner wall 38 of the motor housing 36. The fluid flowthrough these channels may be arranged to provide cooling to the motorhousing 36. This integrated cooling system of the motor housing 36 isenabled by the integration of the manifold 54 into the housing 34, andits axial location next to the motor housing 36, between the motorhousing 36 and the pump housing 46.

The use of a pump 22 such as a gear pump or vane pump within the singlehousing integrated assembly of the embodiment of FIG. 2 is preferable asthe pump 22 provides the assembly with a flexible range of operation. Asthe pump 22 is integrated into the assembly, it is desirable that theassembly is able to be specified across a wide range of operationwithout having to vary the size or configuration of the single piecehousing 34.

In the arrangements of the prior art, if a system specification requiresgreater displacement from the pump a designer may simply specify analternative pump and substitute this pump into the assembly. In thepresent embodiment, if it is required to vary the displacement of thepump, this may achieved by replacing the valve cartridge 25 with analternative configuration. As it is only the internal configuration ofthe cam ring that varies, the pump cartridge 25 still occupies the samespace within the housing 34.

A single assembly which includes an integrated pump, motor and controlmanifold package therefore optimizes the packaging and performance whileminimizing the component parts required. The present embodimentadvantageously reduces the number of parts and therefore cost and spaceclaim. Motor pumps of the prior art typically use two shafts a couplingand four bearings. The present embodiment uses only one bearing with thepump 22 functioning like an oil bearing helping to support the shaft.

Whilst endeavouring in the foregoing specification to draw attention tothose features of the invention believed to be of particular importanceit should be understood that the Applicant claims protection in respectof any patentable feature or combination of features hereinbeforereferred to and/or shown in the drawings whether or not particularemphasis has been placed thereon.

1. A motor pump and control manifold assembly comprising: a motor; adrive shaft connected to the motor; a pump; and a control manifoldincluding means for controlling fluid flow to and/or from the pump,wherein the motor, drive shaft, pump and manifold are contained within asingle common housing.
 2. A motor pump and control manifold assemblyaccording to claim 1 wherein the housing comprises a main housing bodycontaining each of the motor, drive shaft, pump and manifold.
 3. A motorpump and control manifold assembly according to claim 2 wherein themanifold is integrally formed as part of the housing body.
 4. A motorpump and control manifold assembly according to claim 3 wherein themanifold includes an integrally formed pump chamber within which thepump is housed.
 5. A motor pump and control manifold assembly accordingto claim 4 wherein the pump chamber is fluidly connected to the manifoldwithin the housing body.
 6. A motor pump and control manifold assemblyaccording to claim 1 wherein the pump is a gear pump.
 7. A motor pumpand control manifold assembly according to claim 1 wherein the pump is avane pump.
 8. A motor pump and control manifold assembly according toclaim 2 wherein the housing includes an integrally formed chamber forhousing the motor.
 9. A motor pump and control manifold assemblyaccording to claim 1 wherein the drive shaft is a single piece commonshaft connected to both the motor and the pump.
 10. A motor pump andcontrol manifold assembly according to claim 9 wherein only a singlebearing is preferably provided along the drive shaft between the motorand the pump.
 11. A motor pump and control manifold assembly accordingto claim 2 includes an inner wall located axially inwards of the pumpthat defines the porting face of the valve chamber and includes aplurality of ports formed therein arranged to port fluid to and from thepump.
 12. A motor pump and control manifold assembly according to claim11 where a closure member is provided at the axially opposing end of thepump chamber to the porting face to close the pump chamber and securethe pump therein.
 13. A motor pump and control manifold assemblyaccording to claim 12 wherein the closure member forms the axially outerside wall of the pump chamber.
 14. A motor pump and control manifoldassembly according to claim 2 wherein the control manifold is axiallylocated between the pump chamber and the motor chamber.
 15. A motor pumpand control manifold assembly according to claim 14 wherein the housingincludes one or more integrally formed heat exchange fluid channelsarranged proximate the motor chamber to effect cooling thereof.
 16. Amotor pump and control manifold assembly according to claim 15 wherein anetwork of heat exchange fluid channels are formed within the housingproximate the axially inner wall of the motor chamber.
 17. A motor pumpand control manifold assembly according to claim 15 wherein the manifoldis configured to control fluid through the heat exchange fluid channels.18. A motor pump and control manifold assembly according to claim 1comprising at least one control manifold module including one or morevalves, the control manifold module being configured to connect to thecontrol manifold to increase the control functionality of the motor pumpassembly.
 19. A motor pump and control manifold assembly according toclaim 18, wherein the control manifold includes one or more fluid portsarranged for connection to the at least one control manifold module, thecontrol manifold and control manifold module including correspondingconnector elements to enable the control manifold module to be securedto the control manifold.
 20. A motor pump and control manifold assemblyaccording to claim 19 wherein the control manifold module includesconnector elements arranged to enable a further control manifold moduleto be secured thereto.
 21. A motor pump and control manifold assemblyaccording to claim 1 wherein at least the part of the housing comprisingthe control manifold and the pump chamber is a single piece body.
 22. Amotor pump and control manifold assembly according to claim 21 whereinat least the part of the housing comprising the control manifold and thepump chamber is a single piece casting.